Piston for use with rotary piston rod

ABSTRACT

A piston is disclosed which is primarily intended to be used in moving a piston rod lengthwise as such a rod is rotated. Such a piston is intended to be employed in a pipe cleaning device, but may also be utilized for other purposes. The piston itself includes a center member having a cylindrical surface carrying a low friction cylindrical sleeve. This sleeve in turn carries what may be referred to as two elastomeric sealing means. Each of these sealing means has flat surfaces which are arranged so that the surfaces on one of the means face one end of the center member and so that the flat surfaces on the other sealing means face the other end of the center member. Flanges are provided in order to hold the sleeve and the sealing means in position.

United States Patent [1 1 Jai [4 1 Aug. 26, 1975 PISTON FOR USE WITH ROTARY PISTON ROD [76] lnventor: Marlyse Jeanean Baldwin Jai, 3155 French Rd., Apt. 223, Beaumont,

Tex. 77704 [22] Filed: Nov. 17, 1972 [21] App]. No; 307,417

[52] US. Cl. 92/182; 92/2; 92/110; 92/116; 92/158; 92/244; 92/252; 277/DIG. 8

[51] Int. Cl. Fl6j l/02; F16j l/O8; Fl6j H24 [58] Field of Search 92/2, 110, 116, 182, 184, 92/185. 251, 252, 258, 244, 157, 158, 160,

242, 243, 249, 250; 277/DIG. 8

2,803,842 8/1957 Fuller l5/lO4.1

Primary Exuminerlrwin C. Cohen Attorney, Agent, or FirmEdward D. OBrian 5 7 ABSTRACT A piston is disclosed which is primarily intended to be used in moving a piston rod lengthwise as such a rod is rotated. Such a piston is intended to be employed in a pipe cleaning device, but may also be utilized for other purposes. The piston itself includes a center member having a cylindrical surface carrying a low friction cylindrical sleeve. This sleeve in turn carries what may be referred to as two elastomeric sealing means. Each of these sealing means has flat surfaces which are arranged so that the surfaces on one of the means face one end of the center member and so that the flat surfaces on the other sealing means face the other end of the center member. Flanges are provided in order to hold the sleeve and the sealing means in position;

3 Claims, 2 Drawing Figures PISTON FOR USE WITH ROTARY PISTON ROD BACKGROUND OF THE INVENTION This specification is directed towards the construction of pistons which are used in cylinders in conjunction with rotary piston rods. They are intended to be utilized in place of prior piston structures in which such rods are connected to essentially conventional pistons by essentially conventional rotary couplings or bearings. The pistons herein indicated are primarily intended to be used in pipe cleaning machines, but are capable of being employed in other applications.

Conventionally, such pipe cleaning machines have been constructed so as to include a hollow piston rod, a cylinder including a piston attached to the rod for use in moving the rod in a lengthwise direction, a cleaning tool attached to the end of the rod remote from the cylinder. means for rotating the rod as it is moved in the direction of its length and means for conveying a fluid through the rod as it is moved lengthwise and as it is rotated. In a presently preferred type of such a machine the fluid used to move the piston in one direction in the cylinder is also used in connection with a cleaning tool by being conveyed through the rod to the cleaning tool from the side of the piston remote from the cleaning tool itself.

In order to use the fluid satisfactorily in this manner it has been necessary to construct the piston used in the cylinder in such a manner that the piston is connected to the rod employed through the use of a rotary, essentially fluid tight coupling or bearing. It has been relatively expensive and inconvenient to construct a piston so as to include this type of a rotary connection. Further. it is considered that a structure of this type as formed in accordance with prior practice is somewhat inadequate in its sealing and wear characteristics.

SUMMARY OF THE INVENTION An objective of the present invention is to provide a piston for use with an attached rotary piston rod which constitutes an improvement over prior piston structures as are briefly indicated in the preceding discussion. Further objectives of the present invention are to provide pistons as described which may be easily and conveniently manufactured at a comparatively nominal cost, which perform satisfactory when used in their intended manner, which adequately seal against leakage and which may be used for prolonged periods without deterioration in their performance characteristics.

In accordance with this invention these and various other related objectives of the invention are achieved through the use of a piston which comprises an elongated center member having a cylindrical surface, means on one end of this member for connecting it to a piston rod, flange means secured to both of the ends of the center member, a cylindrical sleeve ofa low friction material located around the cylindrical surface between the flanges so as to be capable of rotating on the cylindrical surface and two elastomeric sealing means located on the cylindrical sleeve.

Each of these sealing means include flat ring-shaped surfaces. The flat surfaces on one of the sealing means face one end of the center member and the flat surfaces on the other of the sealing means face the other end of the center member. These surfaces have edges which are capable of fitting within the interior of the cylinder so as to form a seal with the cylinder wall and the sealing means adjacent to these surfaces are capable of deforming when pressure is applied to these flat surfaces so as to tend to push these edges into sealing contact with the interior of such a cylinder.

BRIEF DESCRIPTION OF THE DRAWING The invention is best more fully explained with reference to the remainder of this specification, the appended claims and the accompanying drawing inwhich:

FIG. 1 is a partial sectional view of a pipe cleaning machine utilizing a presently preferred embodiment or form of a piston in accordance with this invention; and

FIG. 2 is a longitudinal cross-sectional view of this piston.

The piston shown in the drawing is constructed so as to utilize the essentially intangible concepts of the invention set forth or defined in the appended claims. These same concepts may be utilized in other differently constructed and somewhat differently appearing pistons through the use or exercise of routine engineering skill.

DETAILED DESCRIPTION In the drawing there is shown a piston 10 in accordance with this invention used within an elongated cylinder 12 in a known type of machine 14 used in cleaning pipes such as the pipe 16 shown in FIG. 1. In order to accomplish this cleaning function the machine 14 employs an elongated piston rod 18 which extends out through an end 20 of the cylinder 12 through a known type of end structure 22. This rod 18 is adapted to be rotated through the use of a conventional means 24 for this purpose.

Neither the structure 22 nor the means 24 is specifically described in detail in this specification since an understanding of these parts of the machine 14 is unnecessary to an understanding of the present invention. Such parts are indicated in detail in the Fuller US. Pat. No. 2,803,842 issued Aug. 27, 1957, entitled Heat Exchanger Tube Reamer. In the machine 14 the piston 10 and the rod 18 are reciprocated through the use of fluid supplied under pressure through a valve 26 to either the end 20 or an end 28 of the cylinder 12.

The piston 10 itself includes an elongated center member 30 which is preferably formed of a dimensionally stable, strong material such as steel or the equivalent so as to have opposed threaded ends 32 and 34 connected by a centrally located passage 36. The end 32 is adapted to be threaded to an end 38 of the piston rod 18 so as to couple the piston 10 to this rod 18. The center member 30 includes an exterior cylindrical surface 40 located intermediate the ends 32 and 34. It also includes a retaining flange 42 located between the surface 40 and the end 32.

A collar 44 is threaded upon the end 34 of the center member 30; this collar 44 includes an outwardly extending flange 46 corresponding to the flange 42. These flanges 42 and 46 are intended to retain a cylindrical sleeve 48 upon a surface 40. This sleeve 48 is preferably formed of a comparatively low friction material such as Nylon, Teflon or the like so as to be sufficiently large in internal diameter so as to be capable of rotating freely around the surface 40 in a path concentric to this surface. In order to prevent binding this sleeve 48 should be slightly shorter 'than the distance between the flanges 42 and 46. Cross passages 50 are formed so as to lead from the passage 36 to between the interior of the sleeve 48 and the exterior of the surface 40.

The sleeve 48 carries two sealing assemblies or means 52 which are separated from one another by a centrally located low friction washer 54 formed out of a material such as Nylon or Teflon. Similar washers 56 are located at the ends of the means 52 adjacent to the flanges 42 and 46 for the purpose of facilitating rotation between these flanges and the various parts carried upon the sleeve 48. Each of the means 52 in the embodiment of the invention itself includes three identical washer-like members 58 of an elastomeric material such as'Neoprene, each of which is shaped as the frustrum of a right circular cone. These members 58 all have flat surfaces 60 leading to circular edges 62 and sloping walls 64 leading away from these edges 62 and the flat surfaces 60 towards the axis of the piston 10.

It will be noted that the sealing means 52 towards the left of the piston as illustrated in FIG. 2 face the end 34. The flat surfaces 60 on the other of the sealing means 52 towards the right of FIG. 2 face the end 32. The various individual washers or members 58 fit closely against one another so that in effect they operate or appear substantially as units. These individual members 58 are located in planes transverse to the axis of the surface 40 and the center member so that the flat surfaces 60 are disposed in planes perpendicular to this axis.

The entire assembly of the means 52 and the washers 54 and 56 is slightly shorter than the space between the flanges 42 and 46 so as to permit rotation. Preferably the means 52 and the washers 54 and 56 fit closely enough around the exterior of the sleeve 48 so that there is no significant rotation or movement between them and the sleeve 48 during the normal operation of the piston 10.

During such operation the piston 10 is fitted within the cylinder 12 as shown in FIG. 1 of the drawing so that the edges 62 contact the interior of this cylinder. Then, through manipulation of the valve 26 a fluid under pressure such as water is introduced into the cylinder 12 in order to move the piston 10 as the rod 18 is rotated in a conventional manner.

As the piston 10 is moved from its position as shown in FIG. 1, the fluid used to move it will not only serve to cause linear movement of this piston 10, but in addition will flow through the passage 36 to within the rod 18 from within this rod 18 to a cleaning tool 66 attached to this rod 18. Here, some of this fluid will be emitted. Since this fluid is under pressure some of it will go out through the passages 50 to between the sleeve 48 and the surface 40. The fluid passing between these two parts will tend to lubricate the sleeve 48 so that it will rotate relatively easily. This permits the rod 18 to be readily rotated as it is moved in a lengthwise or linear manner.

As the piston 10 moves the fluid applied at one end of the cylinder 12 will contact the first flat surface 60 exposed. Because the sealing means 52 are formed of an elastomeric material as shaped as shown, such pressure will cause deformation of the member 58 upon which such a surface 60 is formed. Such deformation will tend to push the edge 62 surrounding such a surface 60 outwardly into effective sealing contact with the interior of the cylinder 12.

With the invention a plurality of the flat surfaces are used on each of the sealing means 52 to insure that a seal is formed in case there should be leakage around a surface 60 and an edge 62 adjacent to an end of the piston 10. Preferably the edges 62 are all dimensioned so as to lightly contact the interior surface of the cylinder 12 except when pressure is applied to the surfaces 60 as explained so that piston movement will not be impeded to any significant extent except to the extent that such movement is impeded as a result of deformation of the edges 62 when pressure is applied to the surface 60.

The piston 10 has one advantage which will not be readily apparent from the preceding discussion. As the valve 26 is operated so as to move the piston 10 in either direction this piston will normally be moved at a rather rapid rate. In practice, the cylinder 12 is rather long, and as a result this piston 10 as it approaches either the end 20 or the end 28 of the cylinder 12 will possess considerable momentum. In the machine 14 these ends 20 and 28 are preferably provided with internal cylindrical collars 68 located so as to project inwardly a comparatively short distance from the interior of the cylinder.

These collars 68 are dimensioned so as to fit around the flanges 42 and 46. As the piston 10 is moved to either of the ends 20 and 28 one of these collars 68 will engage one of the washers 56 so that the momentum of the piston 10 will be absorbed by the various elastomeric or rubber washer-like members 58. This cushions the structure shown against shock resulting from the piston 10 hitting either of the ends 20 or 28. This is considered desirable in preventing damage if this piston 10 is moved unduly rapidly towards either of these ends 20 and 28.

I claim:

l. A piston for use with a rotary piston rod which comprises:

an elongated center member, said center member having a cylindrical surface intermediate its ends,

attaching means formed on one of the ends of said center member for connecting said center member to a piston rod,

flange means secured to both of the ends of said center member, said flange means being located at the extremities of said cylindrical surface,

a cylindrical sleeve of a low friction material located around said cylindrical surface between said flange means, the length of said sleeve being less than the distance between said flange means, the internal diameter of said sleeve being sufficiently large so that said sleeve is free to rotate on said cylindrical surface,

two elastomeric sealing means for sealing against fluid pressure exerted on said piston, each of said sealing means being located on said sleeve so as to extend around said sleeve and fitting closely up against the exterior of said sleeve,

each of said sealing means having a series of ring shaped flat surfaces located perpendicular to the axis of said cylindrical surface and extending outwardly from said sleeve and having a sloping, conical wall leading away from the edge of each of said flat surfaces,

said flat surfaces on one of said sealing means facing one end of said elongated member and the flat surfaces on the other of said sealing means facing the other end of said elongated member,

the edges of said flat surfaces being capable of fitting against the interior of a cylinder so as to form a seal therewith,

said sealing means being capable of deforming when pressure is applied to said flat surfaces so as to tend to push said edges of said surfaces into sealing contact with the interior of a cylinder with which said piston is used,

passage means for conveying fluid from one of the ends of said piston to between said sleeve and said cylindrical surface so that as fluid is applied to said piston to move said piston in a cylinder the applied fluid will serve to lubricate the area between said sleeve and said surface so as to facilitate rotation between said sleeve and said surface.

2. A piston as claimed in claim 1 including:

a piston rod connected to said attaching means, and

wherein said piston rod and said elongated center member are hollow and have their interiors in communication so that when a fluid is applied to the other of said ends of said center member the fluid will flow through said piston and through said piston rod at the same time that such fluid flows to between said sleeve and said surface.

3. A piston for use with a rotary piston rod which comprises:

an elongated center member, said center member having a cylindrical surface intermediate its ends,

attaching means formed on one of the end of said center member for connecting said center member to a piston rod,

flange means secured to both of the ends of said center member, said flange means being located at the extremities of said cylindrical surface,

a cylindrical sleeve of a low friction material located around said cylindrical surface between said flange means, the length of said sleeve being less than the distance between said flange means, the internal diameter of said sleeve being sufficiently large so that said sleeve is free to rotate on said cylindrical surface,

two elastomeric sealing means for sealing against fluid pressure exerted on said piston, each of said sealing means being located on said sleeve so as to extend around said sleeve and fitting closely up against the exterior of said sleeve,

each of said sealing means having a series of ring shaped flat surfaces located perpendicular to the axis of said cylindrical surface and extending outwardly from said sleeve, each of said surfaces terminating in an outwardly extending edge and having a sloping, conical wall leading away from the edge of each of said flat surfaces,

said flat surfaces on one of said sealing means facing one end of said elongated member and the flat surfaces on the other of said sealing means facing the other end of said elongated member,

the edges of said flat surfaces being capable of fitting against the interior of a cylinder so as to form a seal therewith,

said sealing means being capable of deforming when pressureis applied to said flat surfaces so as to tend to push said edges of said surfaces into sealing contact with the interior of a cylinder with which said piston is used. 

1. A piston for use with a rotary piston rod which comprises: an elongated center member, said center member having a cylindrical surface intermediate its ends, attaching means formed on one of the ends of said center member for connecting said center member to a piston rod, flange means secured to both of the ends of said center member, said flange means being located at the extremities of said cylindrical surface, a cylindrical sleeve of a low friction material located around said cylindrical surface between said flange means, the length of said sleeve being less than the distance between said flange means, the internal diameter of said sleeve being sufficiently large so that said sleeve is free to rotate on said cylindrical surface, two elastomeric sealing means for sealing against fluid pressure exerted on said piston, each of said sealing means being located on said sleeve so as to extend around said sleeve and fitting closely up against the exterior of said sleeve, each of said sealing means having a series of ring shaped flat surfaces located perpendicular to the axis of said cylindrical surface and extending outwardly from said sleeve and having a sloping, conical wall leading away from the edge of each of said flat surfaces, said flat surfaces on one of said sealing means facing one end of said elongated member and the flat surfaces on the other of said sealing means facing the other end of said elongated member, the edges of said flat surfaces being capable of fitting against the interior of a cylinder so as to form a seal therewith, said sealing means being capable of deforming when pressure is applied to said flat surfaces so as to tend to push said edges of said surfaces into sealing contact with the interior of a cylinder with which said piston is used, passage means for conveying fluid from one of the ends of said piston to between said sleeve and said cylindrical surface so that as fluid is applied to said piston to move said piston in a cylinder the applied fluid will serve to lubricate the area between said sleeve and said surface so as to facilitate rotation between said sleeve and said surface.
 2. A piston as claimed in claim 1 including: a piston rod connected to said attaching means, and wherein said piston rod and said elongated center member are hollow and have their interiors in communication so that when a fluid is applied to the other of said ends of said center member the fluid will flow through said piston and through said piston rod at the same time that such fluid flows to between said sleeve and said surface.
 3. A piston for use with a rotary pistOn rod which comprises: an elongated center member, said center member having a cylindrical surface intermediate its ends, attaching means formed on one of the end of said center member for connecting said center member to a piston rod, flange means secured to both of the ends of said center member, said flange means being located at the extremities of said cylindrical surface, a cylindrical sleeve of a low friction material located around said cylindrical surface between said flange means, the length of said sleeve being less than the distance between said flange means, the internal diameter of said sleeve being sufficiently large so that said sleeve is free to rotate on said cylindrical surface, two elastomeric sealing means for sealing against fluid pressure exerted on said piston, each of said sealing means being located on said sleeve so as to extend around said sleeve and fitting closely up against the exterior of said sleeve, each of said sealing means having a series of ring shaped flat surfaces located perpendicular to the axis of said cylindrical surface and extending outwardly from said sleeve, each of said surfaces terminating in an outwardly extending edge and having a sloping, conical wall leading away from the edge of each of said flat surfaces, said flat surfaces on one of said sealing means facing one end of said elongated member and the flat surfaces on the other of said sealing means facing the other end of said elongated member, the edges of said flat surfaces being capable of fitting against the interior of a cylinder so as to form a seal therewith, said sealing means being capable of deforming when pressure is applied to said flat surfaces so as to tend to push said edges of said surfaces into sealing contact with the interior of a cylinder with which said piston is used. 